Hyperbaric vessels



Feb; 13, 1968 R. w. JENSEN ET AL 3,368,556

HYPERBARIC VESSELS 4 Sheets-Sheet 1 Filed Jan. 13, 1964 L- o O 4 H \J INVENTORS. Si AAV/Wm/fl 144 LEA/55v R055 7 GARO/V.

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' HYPERBARIC VESSELS Filed Jan 15, 1964 4 Sheets-Sheet 2 Feb. 13, 1968 w, JENSEN ET AL 3,368,556

HYPERBARIC VESSELS Filed Jan. 13, 1964 4 Sheets-Sheet 5 lag/MM Feb. 13,1968 R .W..JENSEN ET AL 3,368,556

HYPERBARIC VESSELS Filed Jan. 13, 1964 4 Sheets-Sheet 4 1/0 0/ 0 OXYGEN 5 FIG, 5. v

United States Patent O "ice 3,368,556 HYPERBARIC VESSELS Raymond W. Jensen and Robert J. Garon, Los Angeles, Calif., assignors to Wyle Laboratories, El Segundo, Calif., a corporation of California Filed Jan. 13, 1964, Ser. No. 337,314 6 Claims. (Cl. 128-204) This invention relates to the chambers of the hyperbaric type and to a mode of operation thereof. The invention has particular utility in the field of mammal oxygenation as an aid in the treatment of a variety of physical trauma or other bodily malfunction.

While the medical profession has long suspected that valuable physiological and remedial eifects may be obtained by the subjection of a patient to increased atmospheric pressure, it has only been very recently that concerted scientific endeavor has been undertaken to realistically determine the value thereof. It is also true that a mere exposure of men or animals to variable atmospheric pressures is not new per se. In general, the compression and decompression effects of such exposures has long been experienced in such areas as tunnel construction, undersea operations and altitude flying. However, recent investigations have shown that the information derived by these prior experiences has only touched the surface. One such area of information relates to oxygenation.

The critical importance of oxygen to life and bodily well being is clear. Deficiency in oxygen assimilation is generally known as hypoxia. This condition may be the result of insufficient oxygen in the alveolar cavities in the mammalian lung or may be related to a deficiency in oxygen transport throughout the body via the blood stream. In the pa-st, many conditions of hypoxia have been corrected by the device of administering substantially pure oxygen to the patient. When such administration takes place in the normal individual and at normal atmospheric pressure, the blood hemoglobin, normally about 97 percent saturated with oxygen, becomes fully saturated. In addition, more oxygen becomes physically dissolved in the blood. Many conditions of hypoxia have thus been corrected. Though the value of oxygen administration at normal pressure has been established for a variety of traumatic physical conditions, it is also well known that such administration is unable to relieve other known conditions of hypoxia.

Recent medical investigations, though not exhaustive, have pointed optimistically to the fact that a high degree of oxygenation may be achieved through the device of having the patient breathe substantially pure oxygen while the latter is in an ambient condition of relatively high pressure. This phenomenon has been termed in the art hyperbaric oxygenation. For example, if a normal person is placed in a pressure chamber and exposed to increased ambient pressure while breathing oxygen, the oxygen pressure in the lung will increase correspondingly, and, the oxygen content of the arterial blood will also rise. Since the hemoglobin almost immediately becomes fully saturated, virtually all of the blood oxygen content increase Will be in the form of physically dissolved oxygen. As a further specific example, it has been found that at an ambient condition of three. atmospheres absolute, the increased oxygen content of the blood would be two to three times greater than breathing oxygen at normal pressure. Medically, this is truly an impressive result and supplies evidence that such oxygen inhalation under sufficiently high pressure will be a major step in overcoming many hypoxia conditions that have heretofore escaped effective treatment.

As noted above, the exposure of man to high air pressure is not, per se, new. The deleterious effects of such exposure have been noted and studied, the most significant Patented Feb. 13, 1968 being decompression sickness (bends), oxygen poisoning and inert gas narcosis. However, the moment substantially pure oxygen is provided a patient for inhalation under hyperbaric conditions, a number of the known problems are compounded and many new problems arise both technical and medical. From the considerations herein briefly set out, it will thus be apparent to those persons familiar with this field, that the circumstances under which heretofore existent pressure chambers may be used is greatly limited.

Obviously, the danger of flash explosion is very great whenever substantially pure oxygen is present. For this reason, it is most desirable to pressurize the hyperbaric chamber with gas mixtures other than pure oxygen leaving the administration of the latter to other independent means. The danger of fire or explosion is further complicated by the fact that in the proposed medical use of the chamber many volatile agents, such as anesthetics, will of necessity be present in the closed environment.

Additional pressurization problems present themselves when consideration is given to the physical requirements of both patient and attending individuals. Desirably, the vessel should be multicompartmented with the capability of selective or simultaneous pressurization of the compartments. Relatively rapid ability to pressurize at least one compartment to about seven atmospheres is required. This is reasonably necessary to afford the desired degree of patient hyperbaric oxygenation and to afford means of relief in the event a chamber occupant becomes afllicted with decompression sickness.

Other facets of the ambient condition in the hyperbaric vessel must be carefully controlled. For example, ventilation must be such that volatile agents be quickly eliminated from the controlled environment. The carbon dioxide and humidity condition of the controlled environment must be kept at nontoxic and comfortable levels. The temperature condition of the environment must be humanly comfortable and provision must be made to accommodate elimination of bodily heat and equipment dissipated heat. It is also desirable to maintain the controlled environment 'free from foreign matter normally found in compressed air such as dirt particles, oil droplets and the like.

In addition to satisfying the mentioned needs, it will be patent that the hyperbaric unit must satisfy the overriding requirement of economy, so that the installation may be made within budgetary demands of medical facilities and thereby be available to the needs of medical patients.

Objects An object of this invention is the provision of a hyperbaric chamber which is usable for medical purposes.

Another object of this invention is the provision of a hyperbaric chamber which provides an environment free from impurities and foreign matter.

Yet another object of this invention is to provide a relatively inexpensive medically usable hyperbaric chamber.

Still another object of this invention is the provision of a hyperbaric chamber with a unique environmental control arrangement.

These and other objects of the invention are achieved by providing a multicompartmented pressure vessel with one or more cryostatic units containing desired normally gaseous material in the cryogenic range, i.e., in liquid state at low temperature and high pressure, and a means to establish communication between the unit or units and the vessel. There are also means operatively associated with the communication means to controllably vaporize and gasify the material and direct same to the vessel at determinable pressure and temperature levels. It has been found that this cryogenic approach to the embodiment and operation of a hyperbaric vessel ideally meets the test of economy and further meets the medical requirements incident to hyperbaric oxygenation.

The novel features that are considered characteristic of this invention are set forth with particularity in the appended claims. The invention itself both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings, in which:

FIGURE 1 is a partially fragmentary, side elevational view of a typical chamber embodiment;

FIGURE 2 is an end elevational view, taken from the left as seen in FIGURE 1;

FIGURE 3 is a partially fragmentary, end elevational view, taken from the right as seen in FIGURE 1;

FIGURE 4 is a fragmentary sectional view taken along line 44 of FIGURE 3;

FIGURE 5 is a detail end elevational view of a preferred mixing valve employed in the invention;

FIGURE 6 is a partially elevational sectional view taken along line 66 of FIGURE 5;

FIGURE 7 is a partially elevational sectional view taken along line 77 of FIGURE 1; and

FIGURE 8 is a schematic representation of a typical flow diagram employed in the invention.

Pressure vessel In FIGURE 1, it will be seen that the arrangement in accordance with this invention comprises an enclosable multicompartmented hyperbaric pressure vessel, indicated generally at 10. Specifically, the vessel comprises a cylindrical central shell 12 and end caps 14 and 16 secured to opposed ends thereof as, for example, by welding A center cap 18 is peripherally secured to the inner surface -of shell 12 as, for example, by welding, to define a plurality of chambers 20 and 22.

An annular flange 24 is secured centrally to end cap 14 by welding. Similarly, an annular flange 26 is secured centrally to center cap 18 by welding. The flanges 24 and 26 are respectively cooperatively associated with access doors indiated respectively generally at 28, and 30 and 32.

It will be understood that all access doors are identical in construction and accordingly, only door 28 will be described in detail.

Considering FIGURES 3 and 4, it will be seen that door 28 comprises arcuate plate 34 having annular plate 36 weldably secured thereto. The plate 36 is provided with an annular machined cavity to receive with a press fit seal element 38. As shown in FIGURE 4, when the door is in closed position, the seal element 38 pressure engages,

as will hereinafter appear, the related surface of flange 50, 50. The holes 48 and 50 are on identical radii from the axis of rotation of pivot rod 44 as seen in end elevational view. Plate 46 also carries inner handle 52.

Pivot rod 44 extends outwardly of bushing 42 and is there fixedly connected to outer handle 54 via collar 56 and pin 58. It will be noted that collar 56 weldably carries plate 60. A pair of conecting rods 62, 62 are provided,

with the inner ends thereof pivotally connected to plate 60 as at 64. Each rod extends generally radially outwardly for pivotal connection to door latching mechanism, indicated generally at 66. Specifically, the mechanism 66 comprises support lug 68 weldably carried by plate 36. Pin 70 offers pivotal mounting of L-shaped latch element 72 to lug 68, the spring 74 being compressively interposed between the pin and lug to eliminate looseness in the arrangement. The latch element 72 comprises locking arm 76 and leverage arm 78, the latter having the extremity thereof pivotally connected at 80 to the adjacent end of the related connecting rod 62. It will be noted that locking arm 78 is provided with cam surface 82 which is angularly related to the vertical, said cam surface 82 being arranged to lockingly cooperate with lug 84, to thereby apply pressure to urge the door 28 and seal 38 into firm engagement with the flange 24. It will thus be understood that upon appropriate rotation of pin 44 by either manual handle 52 or 54 the latching mechanism 66 is brought into a lock or unlock position.

Noting FIGURES 1 and 3, it will be seen that a door mounting hinge system is provided for door 28. Specifically, spaced brackets 84, 84 are fixedly carried by cap 14. Pin 86 interconnects the brackets 84 and accommodates journal mounting of spaced arms 88, 88. In turn, the extremities of arms 88 are journally connected to opposed sections of the door 28 via door mounting pins 90, 90. Thus the door 28 is provided with a multiple axis hinge connection to the vessel 10 minimizing floor area sweep during opening and closing thereof.

It will be recalled that the plates 40 and 46 are provided with holes 48 and 5t} (FIGURES 3 and 4) on identical radii. In the closed position of door 28, as seen in FIGURE 3, it will be seen that said holes 48 and 50 are out of complemental alignment. counterclockwise rotation of pivot pin 44 (FIGURE 3) moves the latching mechanisms 66 to unlock position and, it will also be noted, that such rotation of plate 46 brings the holes 50 into complemental alignment with the holes 48. Thus the unlat-ching of the door 28 establishes communication between the chamber 20 and atmosphere and automatically eliminates any pressure differential that may exist therebetween.

It is to be noted that the medical use of the vessel 10 contemplates occupancy of the chamber for extended periods of time under hyperbaric conditions by both patient and attending personnel. Those familiar with the medical field will recognize the possibility of bodily toxia occurring that would impair the judgment of persons inside. Under such circumstances, it may be possible that persons occupying the chamber would attempt to escape therefrom under conditions where it was medically undesirable for them to do so. Opening of the door 28 from the inside is, of course, possible via the manual handle 52. It will be noted, however, that the external handle 54 is importantly longer than the handle 52 (FIGURE 4). It will be apparent therefore that an external attendant manipulating handle 54 will have a greater mechanical f advantage than an internal occupant attempting to manipulate handle 52. Thus, an external attendant could overpass through device 94. Appropriate flooring is provided for the chambers 20 and 22 by conventionally securing floor plates 96, 96 to the shell 12. Also conventional explosion proof lighting fixtures 98 may be appropriately carried within the vessel.

Flow diagram Consideration will now be given to the system and apparatus employed in the preferred embodiment to controllably create and maintain hyperbaric environment within the vessel 10. As earlier noted, the system employed is cryogenic in nature. For illustrative purposes, the system disclosed in the flow diagram of FIGURE 8 employs cryostats 100 and 102 containing liquid nitrogen and liquid oxygen, respectively. It will be noted, however, that this disclosure is illustrative only and that other cryogenic materials may be employed depending upon the desired environmental conditions within a given vessel. It will also be understood that the cryostatic units disclosed are readily available commercial items, hence the structure thereof need not be shown in detail. For purposes of this disclosure, it is sufficient to note that the cryostatic units provide the cryogenic materials in the liquid state and at extremely low temperature and high pressure. Further, each conventional cryostatic unit is equipped with conventional controllable regulating valve means to maintain predetermined operating pressure within the vessel during cyclic consumption of the cryogenic liquid therein.

More specifically, the cryostats 100 and 102 conventionally are multishelled tanks which store the cryogenic materials. In normal operating conditions these materials are present in the tanks in both a liquid phase condition and gaseous phase condition. The liquid phase condition normally is disposed below the gaseous phase. The conventional mode of maintaining a desired operating pressure within the tanks 100 and 102 is to provide a line such as lines 101 and 103, which establishes communication between the liquid and gaseous phases. Conventional pressure building and regulating valves 105 are disposed in said lines. These valves may be preset to operating requirements. As liquid phase withdrawal from the cryostats is undertaken, liquid container pressure decreases. The pressure building regulating valves 105 open in response to this pressure decrease which allows liquid cryogenic material to enter lines 101 and 103 and there vaporize. The vapor passes to the gas phase section of each cryostat and increases the cryostat pressure to the desired level. The pressure building and regulating valves now close in response to the attaining of cryostat pressure level. The process is repeated as the cyclic withdrawal process continues.

Returning to FIGURE 8, a first withdrawal line 104 is arranged to communicate with the liquid phase of the nitrogen contained in cryostat 100. Line 104 embodies a liquid vaporizer, indicated generally at 106, and comprises a plurality of coils 108 within line 104 disposed in tank 110. A controlled temperature liquid, for example water, is circulated via lines 112, 112 through the tank 110 and in heat exchange relationship with coils 108. Line 104 leaves the liquid vaporizer 106 and establishes communication with nitrogen intake port 114 of first mixing valve 116. A bypass line 118 has opposed ends thereof communicating with line 104 upstream and downstream, respectively, of the liquid vaporizer and in parallel there with. A temperature responsive valve 120 is in series in line 118 and controls flow therethrough in a manner hereinafter described.

A second withdrawal line 122 is in communication with the liquid phase of the oxygen in the cryostat 102 and has the opposed end thereof communicating with oxygen intake port 124 of mixing valve 116. Intermediate the ends thereof the line 122 may be coiled as at 126 so as to be in heat exchange relationship with ambient atmosphere and in effect providing an air vaporizer.

A second mixing valve, indicated generally at 130, has nitrogen intake port 132 communicating with line 104 via line 134. Also the oxygen intake port 136 of valve 130 communicates with line 122 via line 138. Completing the system, outlet port 140 of valve 116 communicates with chamber 20, via line 142, and outlet port 144 of valve 130 communicates with chamber 22 via line 146. Mixing valves 116 and 130 and related piping are clearly shown in FIGURES l and 2.

Mixing valve arrangement Attention is now directed to FIGURES 5 and 6 which teach a detailed construction of the mixing valves employed in the presently preferred embodiment of the invention. For illustrative purposes only valve 116 will be shown and described, it being understood that valve is structurally and functionally identical therewith.

Valve 116 comprises a housing having an intake segment 152. Nitrogen intake port 114 communicates with annular nitrogen intake chamber 154, and oxygen intake port 124 communicates with annular oxygen intake chamber 156. A balance chamber 158 is defined by segment 152 intermediate the intake chambers. A balance spool 160 having opposed identically formed enlarged bearing sections 162, 162 is positioned Within the balance chamber 158 with sections 162 guidably carried by segment apertures 164, 164 to accommodate left and right linear movement of spool 160. Centrally thereof, the spool 160 presents an enlarged section 166 which annularly carries flexible seal 168, the latter being peripherally secured to the wall defining chamber 158. In this manner, the spool 160 and seal 168 divide the balance chamber into two equal noncommunicating volumes. Segment 152 also defines valve seats 170 and 172 immediately adjacent cham bers 154 and 156, respectively, and in operative relation with the adjacent enlarged sections 162 of the spool 160. Nitrogen and oxygen outlet ports 174 and 176, respectively, communicate with the balance chamber 158. Drilled and crossdrilled holes 178 and 180 establish communication between the balance chamber 158 and the openings between the respective enlarged segments 162 and housing 150. Thus, vacuum buildup is prevented therein which would inhibit the motion hereinafter described.

Mixing valve 116 further comprises an outlet segment, indicated generally at 182. It will be seen that outlet segment 182 is provided with an elongated cylindrical aperture 184 extending therethrough and arranged for complemental reception of metering bar member 186. It will now be noted that segment 182 of valve 116 defines a single outlet port 140 previously described. Passages 188 and 190 communicate directly with outlet port 140 and are arranged for physical alignment with ports 174 and 176 of the inlet segment 152 via aperture 184. Flapper members 192 and 194 are arranged to cover passages 188 and 190, respectively, and act as one way check valves to admit gas flow in said passages only in the direction of the outlet port 140.

Directing attention to the metering bar 186 it will be seen that 1t is manually movable, via handle 196 within aperture 184. A plurality of annular slots 198 are formed in the bar 186 and receivably cooperate with spring loaded detents 200, 200 carried by outlet segment 182, whereby said bar may be selectably positioned within the aperture 184.

An important feature of the metering bar 186 is that a plurality of orifices are formed therein. Specifically, these orifices are arranged in pairs as follows: 202 and 202a 204 and 204a; 206 and 206a; 208 and 208a; 210 and 21012? The respective pairs of orifices are so spaced along metering bar 186 so that each pair will establish communication between port 174 and passage 188 and port 176 and passage 190 as the bar 186 is selectably moved to the various detent positions within aperture 184. The operation of this structure will hereinafter be considered in detail. Appropriate conventional seals 201 may be provided where required.

Ventilation means For a consideration of the means employed to controllably vent the hyperbaric vessel, attention is directed to FIGURES 1, 2 and 7. Initially, it will be noted that each chamber 20 and 22 may be provided with emergency relief valve 212, 214 which may be set to the maximum pressurization desired within the vessel 10.

In normal operation, however, ventilating arrangements indicated generally at 216 and 218 are employed. Arrangement 218 includes pipe 220 which directly communicates with chamber 20, while arrangement 218 includes pipe 222 which directly communicates with chamber 22. It will be understood that ventilating arrangements 216 and 218 are functionally and structurally identical hence only arrangement 216 will be herein described in detail.

Pipe 220 of arrangement 216 establishes communication between chamber 20 and intake port 224 of vent valve 226 (FIGURES 2 and 7). Valve 226 includes outlet port 228 which vents to atmosphere. Controlled venting of chamber 20 to atmosphere is achieved via gate means comprising guidably movable valve stem and poppet plate 230 which cooperatively engages valve seat 232 and the operatively connected pressure linkage system, indicated generally at 234. The linkage system 234 comprises lever 236 which is fulcrumed to the vessel 10 via pivot 238. Pressure from the lever 236 is transmitted to the valve stem 230 via pivotally carried bar 240 and interposed ball 242. This structure avoids biasing forces being applied to stem 230 which could tend to bind same. A rod 244 has the upper end thereof pivotally connected, as at 246, to one end of the lever 236 and the lower end thereof pivotally connected, as at 248, to a balance arm 250 intermediate the ends of the latter. A bracket 252 is weldably secured to end cap 16 of the vessel 10 and provides a fulcrum 254 about which the balance arm 250 may move. A balance weight 256 is pivotally carried by the arm 250 on one side of fulcrum 254 while that segment of the arm 250 on the opposite side of fulcrum 254 threadably carries adjustable weight 258.

Operation Initial consideration will be given the flow diagram of FIGURE 8 for an understanding of the operation of the invention. Valves 260 and 262 control the flow of liquid phase cryogenic material from the respective tanks 100 and 102. Vessel 10 may be equipped with conventional pressure and temperature indicating gages 264 and 266, respectively, which advise the operator of the pressure and temperature levels existent in the chambers 20 and 22. Chambers 20 and 22 may be selectively or concurrently controlled by the opening or closing of valves 268 and 270. Additionally, valves 260 and 262 may be selectively opened and closed to create a hyperbaric environment in vessel 10 resulting from a combination of cryogenic sources or from a single cryogenic source. For illustrative purposes herein, consideration will be given to the operation resulting from use of a combination of cryogenic sources, specifically, the cryostat source tanks 100 and 102 containing liquid phase nitrogen and oxygen, respectively.

Each cryostat 100 and 102 is conventionally set at a predetermined desired internal operating pressure, such operating pressure being maintained throughout the cycle of cryogenic material flow therefrom. If desired, relief valves 272 and 274 may be conventionally utilized to assure maximum pressure existent in the cryostats.

Liquid nitrogen is carried, via line 104, to liquid vaporizer 106, where, by means of heat exchange, it is vaporized and converted to the gaseous state. The temperature level of the gaseous nitrogen is controlled by controlling the temperature level of the heat exchange material, preferably water, within the tank 110. The gaseous nitrogen is then carried to the mixing valves 116 and 130.

Liquid oxygen is concurrently carried, via line 122, to coils 126 where it is in heat exchange relation with ambient atmosphere. As a result of heat addition thereto, via this atmospheric vaporizer, it is vaporized and converted to the gaseous condition and carried to mixing valves 116 and 130.

Attention is now directed to FIGURES 5 and 6 for an understanding of the operation of the mixing valves 116 and 130. Gaseous nitrogen enters the mixing valve via port 114 while gaseous oxygen enters the valve via port 124.

Because of the predetermined selected setting of the operating pressures of the cryostats and 102, the gases enter said mixing valve under substantially equal pressure conditions. From entrance chambers 154 and 156 the gases pass into balance chamber 158. Because of the similar pressure levels on opposite sides thereof the balance spool 160 maintains a central position in the chamber 158. From chamber 158 the nitrogen and oxygen escape, via ports 174 and 176, through the aligned metering rod 186 orifices and into passages 188 and 190. From passages 188 and 190 the gases respectively pass flapper check members 192 and 194, intermix, and pass through outlet port 140 and into the respective chambers of vessel 10.

It will be apparent to those skilled in the art, that the preselected operating pressure of cryostats 100 and 102 minus line drop loss, would, with the structure just described, determine the unit pressure level existent in the vessel 10. To offer operator control of the pressure level in vessel 10, attention is again directed to the ventilating arrangement 216 shown in FIGURES 2 and 7.

As the pressure builds up in vessel 10, intelligence as to the level thereof is given the operator via guages 264. As the desired level is approached, the operator repositions the threadably mounted adjustable weight 258 on balance arm 250, thereby varying the force transmitted to the valve stem 230 via connected lever 236. As the weight 258 is moved outwardly, as seen in FIGURE 2, on the arm 250, the closing force on stem 230 will be greater and the valve 226 will vent to atmosphere at a higher unit pressure thus maintaining a higher pressure level within the vessel 10. Conversely, as the weight is moved inwardly on arm 250, the closing force exerted on stem 230 will be less and venting to atmosphere will occur at a lower pressure level. By precisely controlling the position of the weight on the arm 250 the operator may accurately control the pressure level within the related chamber. Summarizing, it will be apparent that accurate pressure levels may be obtained in vessel 10 by controlling the ventilation rate thereof.

Attention is again directed to metering valve 116 as shown in FIGURES 5 and 6. It will be recalled that the metering rod 186 is provided with paired orifices which accommodate passage of gaseous nitrogen and oxygen to the vessel 10. Those skilled in the art will understand that the paired orifices may be sized to admit to the vessel 10 any desired proportion, by volume, of gaseous nitrogen and oxygen. With uniform nitrogen and oxygen operating pressure it is only necessary that each pair of orifices bear a predetermined area relationship relative to each other. For example, using the disclosed circular orifices if the nitrogen admitting orifices on the left section of FIGURE 6 are provided with a diameter approximately double the diameter of the oxygen admitting orifices on the right section of the figure the controlled environment in vessel 10 will comprise approximately 81% nitrogen and 19% oxygen by volume. 'If, while maintaining the same relative orifice pair proportion, the physical size of the orifice pair is increased, the flow rate, per unit of time, of gaseous nitrogen and oxygen into the vessel .10 will be increased. As an illustrative example of satisfactory hyperbaric operation, the cryostats 100 and 102 may be set at an operating pressure of approximately p.s.i. absolute. The operatively paired orifices may be given respective diameters as follows: 202 and 202a,

0.1718 and 0.3438; 204 and 204a, 0.125" and 0.250; 206 and 206a, 0.0625" and 0.1250; 208 and 2080, 0.0468" and 0.0938"; 210 and 210a, 0.0313" and 0.0625". With the suggested operating pressure and orifice dimensions there will result a delivery to the vessel 10 of an environment containing approximately 81% nitrogen and 19% oxygen by volume. As the metering rod is reset to utilize the larger diameter paired orifices the flow rate of the gases in the mentioned relative proportions will increase.

Further, at the suggested operating pressure and with the suggested orifice dimensions the hyperbaric vessel may readily be controlled at any pressure level from one to seven atmospheres.

The feature of being able to control the flow rate While maintaining vessel pressure level is of importance in controlling carbon dioxide level within the vessel. As noted above, carbon dioxide toxia could affect persons within the vessel. To avoid the ill effects of carbon dioxide toxia under increased pressure within the vessel it is recommended that the flow rate through the vessel be increased by three cubic feet per vessel occupant for each pressure atmosphere above normal. The operator may easily achieve any desired flow rate by resetting the metering rod of each metering valve and adjusting the ventilating arrangement to achieve desired pressure level.

Recalling that temperature control is extremely important in the contemplated medical use of the vessel, attention is again directed to the fiow diagram of FIGURE 8. Note that the operator is advised of the existing temperature level within the vessel 10 by observing temperatu-re guages 266. Primary temperature control within the vessel 10 is offered by raising the oxygen temperature to ambient in air coils 126 and controlling the temperature level of the heat exchange liquid in tank 110 with nitrogen gas temperature. If, in a given circumstance, refined temperature control proves inadequate using these methods, valve 120 in parallel line 118 may be opened to bleed low temperature nitrogen to the mixing valves. In this manner, a secondary temperature control mode is provided.

The mixing valve of FIGURES 5 and 6 presents another feature to insure safe operation of the entire system. It will be recalled that the spool 160 is movably carried in the intake segment of valve 116. In the unlikely event that a differential should result in the operating pressures of cryostats 100 and 102, it will be promptly reflected in a pressure differential existent in the balance chamber on opposite sides of the diaphragm seal 168. This differential will induce motion of the spool in the direction of the lower level restricting gas flow of the higher pressure line from the entrance chamber and accommodating a greater flow volume from the entrance chamber lower pressure line. For example, should the pressure at intake port 114 fall while the pressure at intake port 124 remains at the higher level, the differential existing in balance chamber 158 will cause the spool 160 to move to the left as seen in FIGURE 6. This will accommodate a larger flow volume from entrance chamber 154 to balance chamber 158, and, concurrently, the flow volume from chamber 156 will be reduced or restrictively bled as a result of spool movement. Additionally, any momentary back flow from the higher pressure line to the lower pressure line is prevented by flapper valve check members 192 and 194.

It will thus be apparent to those skilled in the art that the described invention provides a unique hyperbaric system specifically adaptable for medical use. The system and the adoption therein of cryogenic materials provides an economic mode of ofiering easily controllable hyperban'c environment. The environment provided is chemically pure, clean and relatively dry. The system offers accurate and simple pressure and temperature control and is readily adaptable to a wide variety of uses.

The invention as disclosed is by way of illustration and not by way of limitation, and may be subject to modification without departing from the scope of the appended claims.

What is claimed is:

1. In a hyperbaric vessel arrangement, an enclosable pressure vessel, a first source of cryogenic material in liquid phase condition at low temperature and high pressure, a second source of other cryogenic material in liquid phase condition at low temperature and high pressure, a first withdrawal line communicating with said first source, a second withdrawal line communicating with said second source, pressure means operatively associated with the respective sources to induce movement of the cryogenic materials through the respective lines, vaporizing means within the respective lines to convert the respective materials to gaseous phase condition, said vaporizing means including heat exchange means to raise the temperature of the cryogenic materials in the respective lines to predetermined levels; gas mixing means in operative communication with the respective lines and operative to physically intermix the gaseous materials, said gas mixing means including valve means having a first intake port communicating with said first withdrawal line, a second intake port communicating with the second withdrawal line, orifice means operatively associated with the respective lines and arranged to proportion the flow of the respective gaseous materials therethrough in determined relation to each other by volume, said orifice means being in communication with said conveying means thereby accomplishing intermixture of said gaseous materials, conveying means establishing communication between the mixing means and the vessel and arranged to deliver intermixed gaseous material thereto to create in the vessel a pressure condition greater than atmospheric, and vent means to controllably vent said vessel in response to the pressure conditions therein while maintaining the pressure therein greater than atmospheric.

2. A hyperbaric vessel arrangement according to claim 1, and including means operatively associated with the orifice means to controllably vary the size thereof and thereby control the flow rate of the respective gaseous materials to the vessel.

3. A hyperbaric vessel arrangement according to claim 1, wherein said vent means comprises a valve having a vent intake port communicating with the vessel and a vent exhaust port communicating with the atmosphere, gate means within the valve operable to selectably open to establish communication between the vent intake port and vent exhaust port in response to a predetermined pressure level within the vessel and thereby vent the vessel to atmosphere.

4. A hyperbaric vessel arrangement according to claim 3, and including control means operatively connected to the gate means and arranged to controllably vary the opening of said gate means in response to different unit pressure levels within the vessel.

5. A hyperbaric Vessel arrangement according to claim 4, wherein said gate means comprises a poppet plate, said control means comprising mechanical means to variably pressure urge the poppet plate to closed position.

6. A hyperbaric vessel arrangement according to claim 5, wherein said poppet plate is carried by an elongated stem and guidably moved therewith along the axis thereof, said mechanical means comprising a pressure lever operatively engaging the stem to pressure urge the plate to closed position, a fulcrumed balance arm having weight means controllably movable therealong, and linkage interconnecting the arm and pressure lever, the pressure exerted by said lever on said stem responding to the position of the weight means on said arm.

References Cited UNITED STATES PATENTS 659,263 10/1900 Smith 137-532 X 1,224,180 5/1917 Lake 128204 1,459,158 6/1923 Lisse 128203 2,244,082 6/1941 Reyniers 1281 2,373,333 4/1945 St. Onge 128204 X 3,215,057 11/1965 Turek 128-l42 X RICHARD A. GAUDET, Primary Examiner.

ROBERT E. MORGAN, Examiner.

W. E. KAMM, Assistant Examiner. 

1. IN A HYPERBARIC VESSEL ARRANGEMENT, AN ENCLOSABLE PRESSURE VESSEL, A FIRST SOURCE OF CRYOGENIC MATERIAL IN LIQUID PHASE CONDITION AT LOW TEMPERATURE AND HIGH PRESSURE, A SECOND SOURCE OF OTHER CRYOGENIC MATERIAL IN LIQUID PHASE CONDITION AT LOW TEMPERATURE AND HIGH PRESSURE, A FIRST WITHDRAWAL LINE COMMUNICATING WITH SAID FIRST SOURCE, A SECOND WITHDRAWAL LINE COMMUNICATING WITH SAID SECOND SOURCE, PRESSURE MEANS OPERATIVELY ASSOCIATED WITH THE RESPECTIVE SOURCES TO INDUCE MOVEMENT OF THE CRYOGENIC MATERIALS THROUGH THE RESPECTIVE LINES, VAPORIZING MEANS WITHIN THE RESPECTIVE LINES TO CONVERT THE RESPECTIVE MATERIALS TO GASEOUS PHASE CONDITION, SAID VAPORIZING MEANS INCLUDING HEAT EXCHANGE MEANS TO RAISE THE TEMPERATURE OF THE CRYOGENIC MATERIALS IN THE RESPECTIVE LINES TO PREDETERMINED LEVELS; GAS MIXING MEANS IN OPERATIVE COMMUNICATION WITH THE RESPECTIVE LINES AND OPERATIVE TO PHYSICALLY INTERMIX THE GASEOUS MATERIALS, SAID GAS MIXING MEANS INCLUDING VALVE MEANS HAVING A FIRST INTAKE PORT COMMUNICATING WITH SAID FIRST WITHDRAWAL LINE, A SECOND INTAKE PORT COMMUNICATING WITH THE SECOND WITHDRAWAL LINE, ORIFICE MEANS OPERATIVELY ASSOCIATED WITH THE RESPECTIVE LINES AND ARRANGED TO PROPORTION THE FLOW OF THE RESPECTIVE GASEOUS MATERIALS THERETHROUGH IN DETERMINED RELATION TO EACH OTHER BY VOLUME, SAID ORIFICE MEANS BEING IN COMMUNICATION WITH SAID CONVEYING MEANS THEREBY ACCOMPLISHING INTERMIXTURE OF SAID GASEOUS MATERIALS, CONVEYING MEANS ESTABLISHING COMMUNICATION BETWEEN THE MIXING MEANS AND THE VESSEL AND ARRANGED TO DELIVER INTERMIXED GASEOUS MATERIAL THERETO TO CREATE IN THE VESSEL A PRESSURE CONDITION GREATER THAN ATMOSPHERIC, AND VENT MEANS TO CONTROLLABLY VENT SAID VESSEL IN RESPONSE TO THE PRESSURE CONDITIONS THEREIN WHILE MAINTAINING THE PRESSURE THEREIN GREATER THAN ATMOSPHERIC. 